Quantitative analysis of palm carotene using Fourier transform infrared and near infrared spectroscopy

beta-carotene content is usually determined by using ultraviolet (UV)-visible spectrophotometry at 446 nm. In this study, two spectroscopic techniques, namely, Fourier transform infrared (FTIR) and near infrared (NIR) spectroscopy, have been investigated and compared to UV-visible spectrophotometry to measure the beta-carotene content of crude palm oil (CPO). Calibration curves ranging from 200 to 800 ppm were prepared by extracting beta-carotene from original CPO using open-column chromatography. Separate partial least squares calibration models were developed for predicting beta-carotene based on the spectral region from 976 to 926 cm(-1) for FTIR spectroscopy and 546 to 819 nm for NIR spectroscopy. The correlation coefficient (R-2) and standard error of calibration obtained were 0.972 and 25.2 for FTIR and 0.952 and 23.6 for NIR techniques, respectively. The validation set gave R-2 of 0.951 with standard error of performance (SEP) of 25.78 for FTIR technique and R-2 of 0.979 with SEP of 19.96 for NIR technique. The overall reproducibility and accuracy did not give comparable results to that of spectrophotometric method; however, the standard deviation of prediction was still within +/- 5% beta-carotene content over the range tested. Because of their rapidness and simplicity, both FTIR and NIR techniques provide alternative means of measuring beta-carotene content in CPO. In addition, these two spectroscopic techniques are environmentally friendly since no solvent is involved.